Melatonin for Sleep: What It Does, and What It Cannot Do

TL;DR

• Melatonin is a hormone your body releases as darkness falls, signalling biological night.
• On the EU authorised list, melatonin contributes to the reduction of the time taken to fall asleep, and to the alleviation of subjective feelings of jet lag.
• Those benefits come at low doses, around 0.5mg to 1mg, taken at the right time.
• It works as a timing signal for circadian problems like jet lag and shifted schedules, and it isn't a general sedative.
• In much of Europe, higher-dose melatonin is a prescription medicine, so regulation varies by country and dose.

Melatonin is the most reached-for sleep supplement in the world, and also one of the most misunderstood. It's a timing signal, and knowing that changes what to expect from it. Here's what melatonin does, the authorised claims behind it, and the situations where it doesn't do much.

What melatonin is

Melatonin is a hormone made by the pineal gland in the brain. Its release is governed by light: levels stay low during the day, begin rising in the evening as it gets dark, peak in the middle of the night, and fall toward morning. That nightly rise is the body's internal signal that it's time for sleep, part of the circadian system covered in circadian rhythm explained.

Taken as a supplement, melatonin adds to that signal. It tells the body's clock that night has arrived, which is why timing matters as much as dose.

What the authorised claims say

Melatonin is one of the few sleep-related substances with authorised EU health claims, and both are specific. Melatonin contributes to the reduction of the time taken to fall asleep, a claim that applies at 1mg taken close to bedtime. And melatonin contributes to the alleviation of subjective feelings of jet lag, which applies at a minimum of 0.5mg taken close to bedtime on the day of travel and the following few days.

Both claims sit at low doses, and both are about timing and sleep onset, not about depth or duration of sleep.

What it does well

Melatonin's strengths follow from its role as a timing signal. It's most useful when the problem is circadian: jet lag, shift work, and delayed sleep timing, where the body clock is out of step with the clock on the wall. In those situations, a low dose at the right time can nudge the clock and shorten the time to fall asleep. A 2005 meta-analysis found the effect on sleep onset was real but modest, and that higher doses did not do better than low ones (Buscemi et al., 2005).

What it cannot do

Melatonin's effect comes from its timing role, so it works when the problem is circadian. For sleep problems with different roots, the evidence points elsewhere. High doses don't add much: the research supports low, physiological amounts, and the 5mg and 10mg products common on shelves go beyond what the evidence supports. Regular high-dose use is also linked to morning grogginess and other effects, covered in melatonin side effects. For the compounds people turn to when timing isn't the issue, see melatonin alternatives.

Dose, timing, and regulation

The doses tied to the authorised claims are low, 0.5mg to 1mg, taken close to bedtime, or before bed on travel days for jet lag. More is not better. Timing is the lever that matters most, because melatonin works by shifting the body clock.

Regulation is worth knowing. In much of Europe, melatonin above a certain dose is classed as a prescription medicine, so availability and legal dose vary by country. Anyone who is pregnant, breastfeeding, taking medication, or managing a health condition should check with a healthcare professional before using it.

Frequently asked questions

Does melatonin help you sleep?

At low doses taken at the right time, melatonin contributes to the reduction of the time taken to fall asleep, an authorised EU claim. It works best for circadian problems like jet lag and shifted schedules, and it isn't a general sedative.

How much melatonin should I take?

The authorised claims sit at 0.5mg to 1mg, taken close to bedtime. Higher doses haven't been shown to work better, and the research supports low, physiological amounts.

Is melatonin a sleeping pill?

No. It's a timing hormone that signals biological night. It shifts the body clock to signal night, which is why it suits circadian problems more than general insomnia.

Is melatonin safe?

At low doses it has a good short-term safety record. In much of Europe, higher-dose melatonin is a prescription medicine. Anyone who is pregnant, breastfeeding, taking medication, or managing a health condition should check with a professional first.

Disclaimer

This article is for general information and education only. It is not medical advice, and it does not diagnose, treat, or prevent any condition. Melatonin is regulated differently across countries and doses. If you are pregnant, breastfeeding, taking medication, or living with a health condition, speak with a qualified healthcare professional before using it.